Hollow girder



Jan. 17, 1928. 1,656,871 7 B. SCHNITZER HOLLOW GIRDER Filed Feb. 27. 1926 2 Sheets-Sheet 1 74 Belg/0122122 Sc/mzlzer,

61cm new Jan. 17, 1928. 116563871 B. SCHNITZER HOLLOW GIRDER Filed Feb. 27. 1926 2 Sheets-Sheet 2 B Qzykzmin 50122217291;

Patented Jan. 17, 1928.

UNITED srArl-is p K 1,656,871, PATENT" OFFICE.

BENJAMIN SGHNITZER,'OF AKRON, OHIO, ASSIGNOR TO GOODYEAR-ZEPPELIN COB- POBATION, OF AKRON, OHIO, A CORPORATION OF DELAWARE.

HOLLOW, G anna.

My invention relates to light weight girder structures, particularly suitable for use in rigid or semi-rigid airships, and it has particular relationto the construction and ar- 5 rangement of the individual elements which com ose the so-called box girder type.

T e invention herein disclosed is directed to improvements in air craft'girders of the eneral type disclosed in an application of arl Arnstein, Serial No. 727 ,849, filed July 23, 1924, and assifgned to Luftschiflbau Zepv t metal of uniform thickness,- although in pelin Gesellsoha mit Beschrankter Haftung, of Friedrichshafen, Bodensee, Germany.

One object of my'invention is to provide a girder which is composed of light weight material and is so constructed that it is particularly adapted to withstand compression forces. a

Another object of my invention is to provide a box type girder which is constructed of a pluralityof metal plates so formed and arranged that all of the edges of the plates project inwardly and the corner portions 2 are curved, thereby presenting'smooth, surfaces upon which the relatively fragile gas bags or envelope material may rest without possibility of injury thereto.

Another object of my invention is to provide a box girder in which all outwardly disiposed edges are obviated.

n the manufacture of hollow girders or beams, which have heretofore been employed in building the superstructure-of rigid air- 25 ships, relativelythm sheets of material have been employed. ,In order to increase the effectiveness of these girders against compression forces, ribs- 017 similar outwardlyprojecting edges have been provided for stiffen- 4o mg purposes.- These outwardly 'propctmg edges were objectionable because it was necessary to cover them with fabric or similar material in order to avoid injury to the gas bags'and to the outer covering or envelope '4 of the airships which came into contact; girder shown in Fig. 1;

therewith." I v One of the primary advantages of my invention, as herein disclosed, liesin the provision of a-box girder in which the undesirable, outwardly projecting. edges are obviated and effective reinforcing elementsare disposed entirely within the outer contour of the girder. This is accomplished by employing members of channel shape, whose flanges are provided withinwardly bent edges, the flanges in turn being connected to web members of the girder. Recess'es or depresslons are provided in the web members to receive the inturned edges of the channel flanges. Both the channel members and the Webs are punched to provide flanged weight reducing openings, the bent flanges of the openings serving as stiflening members.

Asa general, rule, girders of the general type designated are constructed of sheet flanges of the channel members and adja-' cent web members. Thus relatively light thin channel and web members may be employed and the saving in the amount of material punched from such members to pro-' vide weight reducing openings is an imporbeing thicker at its tant item. As the size of the reinforcing 7 strips may be varied according to the degree of strength required, it is only necessary to maintain in stock relatively few thicknesses ofi channel and web material.

For a better understanding of my invention, reference maynow be had to the accompanyihg drawings forming a part of this specification, of which;

Fig. 1 is a fragmentary elevational view of a girder embodying my invention;

.Fig. 2 is a fragmentary plan view of'the Fig. 3 is a cross-sectional view of a girder embodying my invention, the section being taikpinsubstantially along the line IIL-III 0 1g, 1 V

Fig. 4 is a cross-sectional view of a girder similar to that shown in Figsil and 2, illustrating another form which my invention may assume ig. 5 1s a fragmentary cross-sectional view on an enlarged scale illustrating in detail the structure of'one of the corner portions of the girder shown in Fig. 4;

Fig. 6 is a cross-sectional view of a girder similar to that shown in-Figs. 1 to 3, illustrating another form which my invention may assume;

Fig. 7 is across-sectional view of a girder somewhat similar to that shown in Fig. 3;

Fig. 8 is a cross-sectional view of a embodying my invention, in which the flanges of the weight reducing openings are turned outwardly;

Fig. 9 is a cross-sectional view of a triangular girder embodying my invention; and

Fig. 10 is a cross-sectional view of a girder embodying another form which my invention may assume.

In practicing my invention, I provide a girder, generally indicated by the numeral 20, which is composed of two oppositely disposed channel members 22 and 23 and two oppositely disposed web members 24 and 25. Although I have illustrated in the drawings a boxgirder having four sides, it is to be understood that any convenient number of sides may be employed according to the shape of the girder desired to be constructed.

Each of the channel members 22 and 23 is provided with flanges 26 and 27, respectively, which are riveted, as indicated at 28 and 29, and overlap the adjacent edges of the web members 24 and 25. The edge portions of the channel flanges 26 and 27 are provided with reentrant bent edges or flanges 30 and 32, which are adapted to project inwardly within longitudinally extending recesses 33 and 34, in the web members 24 and 25. At the extremities of the overlapped portions of the web members 24 and 25, flanged edge portions 35 and 36 are provided, which serve to strengthen the corner portions of the girder.

The channel plates 22 and 23 are provided with a series of weight reducing openings 37 and 38, which are punched therefrom and are surrounded by stiffening flanges 39 and 40, extending inwardly with respect to the assembled girder. Smaller flanged weight reducing openings 41 (Fig. 2) are punched adjacent the larger openings in the channel members. Likewise, small'weight reducing openings 42 and relatively large weight reducing openings 43 and 44 are punched in the web members 24 and 25, thelatter being provided with flanges 45 and 46 extending outwardly with respect to the girder. It will be observed by reference to Fig. 3, that the extremities of the flanges 45 and 46 are located inwardly from a plane coinciding with the outer surface of the channel flanges 26 and 27, and that the outer surfaces of the channel members 22 and 23 are smooth. The corner portions of the girder are smoothly curved, as indicated at 47. Thus girder it will be apparent that an airship envelope or gas bag (not shown), upon engagement with the girder, either against the channel members or against the web members, will not engage any sharp edges which would cause injury thereto. All of the extreme edges 30 and 32 are turned inwardly to preof the flanges 52 is riveted, as indicated at 55 to the web members, and is provided with a reentrant edge portion 56, which is adapted to extend toward inwardly bent portions 57 of the web members. It will be observed that the weight reducing openings 58 of the web members are provided with inwardly extending flanges 59 and that overlapped edge portions of the webs 54 are provided with inwardly turned edge portions 60.

As best shown in Fig.5, each of the corner portions of the girder is reinforced by a separate strip 62, riveted between the flanges 52 and the webs 54. This strip is 'bent and provided with a reentrant strengthening edge portion 63. The size and shape of the reinforcing member- 62 may be varied according to the most desirable proportion of weight to strength obtainable for a certain structure of girder. By this structure, relatively thin web channel members may be employed without reducing the efliciency of the girder. This is very important from a standpoint of saving the material punched from the sheets of metal in the formation of weight reducing openings. The structures illustrated in Figs. 4 and 5 rovide smooth outer surfaces to prevent in ury of airship envelope or gas bags-in substantially the same manner as that described and shown in connection with Figs. 1 to 3.

In the event it is desirable to impart additional strength' to the girder between the corners thereof, pairs of web members 64 and 65 ma be employed as embodied in the .structure lllustrated in Fig. 6. The outer contour of the girder in this instance is substantially the same as that shown in Fig. 3. Channel members 66 provided with punched flanged openings 66 and with flanges 67 are riveted, as indicated at 68, to the pairs of web members 64 and 65. It will be observed that flanges 69 and 70 of. the web members extend in opposite directions, and that their edge portions 72 and 73 are turned inwardly in the same manner as the edge portions of the web members shown in Figs. 1 to 3.

The girder embodyin the form of my invention illustrated in F igs. 7 and 8 consists of channel members 7 4 and web members 75, which are connected together to provide corner portions substantially the same as those shown and described with reference to Fig. 3, and further description of these corner portions is accordingly not required for a thorough understanding thereof. In Fi 7, I have illustrated flanges 76 surroun ing weight reducing openings 77. The flanges extend inwardly of the girder, while in Fig. 8 the flanges 7 6 of the weight reducing openings extend outwardly, but not to the outer contour of the girder, as defined by lines drawn from corner to corner thereof.

-It is to be understood that the web mem-- bers 75 may be reinforced by additional plates 77 indicated in dot and dash lines of Fig. 7, thereby providing a air of web plates at each side of the gir er. In this arrangement of pairs of web plates ,the flanges around the openings of the outer plates 7 5 extend inwardly, whereas the flanges surrounding the openings of the inner plates 77 are turned outwardl I Fig. 9 illustrates a girder of su stantially triangular cross-section, in which web members? 8 are secured to channel members 79, the latter being provided with reentrant edge portions 80. All of the corners of the structure illustrated in this figure are curved and the ed es of the channel and web members extcn inwardly to prevent injury to airship envelope or gas bags. Flan ed weight reducing openings 82 are provi ed, which openings function inthe manner de scribed above in connection with the other forms of my invention.

The structure shown in Fi 10 illustrates a form of my invention in w ich web members 83 are connected to each other in overlapping relation. Adjacent one edge of each web member a flange 84 is provided which overlaps the edgeportion 85 of the adjacent web member. The web members are provided with flanged weight reducing openings 86, Although channel. members having two equall large flanges are not employed in this em odiment of my invention, it will be observed that the corner structure of the girder is substantially the same as that described above in connection with the other forms of my invention.

From the foregoing description it will be apparent that I have provided a girder structure which is well balanced, and which is of relatively light weight in proportion to its strength.- Thus a saving of material as well as increased efiiciency in withstanding aerodynamical forces will "result from the use of girders of" this construction in the building of aircraft of the type mentioned.

Although I have, illustrated but the preferred forms which my invention may assubstantially in alignment with the outer surface planes of the girder, the inner overlapping members being provided with depressions to receive the edge flanges of the outer overlapping members, each member being provided with flanged weight reducing openings. I

2. A quadrilateral hollowgirder comprising -oppositely disposed sheet metal webs provided with edge flanges extending in-.

wardly of the girder, oppositely disposed sheet metal channel members connected to the webs, each web and channel member being provided with weight reducing openings and flanges surrounding each opening, the flanges surrounding. the openings of the webs extending in one direction with respect to the interior of the girder and the flanges surrounding the openings of the channel members extending in the other direction with respect to the interior of the girder.

3. A hollow girder polygonal in crosssection comprising oppositely disposed sheet metal webs provided with edge flanges extending, inwardly of the girder, o positely disposed sheet metal channel mem rs connected to the webs, each web'and channel member being. provided with weight reducing openings and flanges surrounding each opening, the flanges surrounding the openings in the webs extending outwardly with respect to the irder.

4. A box gir er comprising interconnected sheet metal members provided with edge flanges extending ,inwardly of the girder and a separate reinforcing strip connected to and inclosed by the sheet metal members adjacent each corner portion of the girder, said strips being bent along one edge thereof.

y 5. A box girder comprising interconnected sheet metal members provided with reentrant edge flanges and a se arate reinforcing strip arranged between t e edge portions of the metal members adjacent reentrant flanges at each corner of the girder, said strips being {provided with flanges turned inwardl w1th respect.tothe girder.

- 6. A ox girder com risin mterconnected metal channel and we mem ers each bein provided with reentrant edge flanges, eac

loo

metal member being provided with a plurality of Weight reducing openings, flanges surrounding the openings extending inward- 1y of the girder and a reinforcing strip of substantially the same width as each leg of the channel members, said strips being secured between the legs of the channel mem- I1321's and the edge portions of the web memrs. 7. A box girder comprising oppositely disposed sheet metal webs provided with reentrant edge flanges, oppositely disposed sheet metal channel members provided with reentrant flanges connected to the webs, each web and channel member bein provided with weight reducing openings, anges surrounding veach opening and reinforcing strips connected within the channel members flush with the legs thereof adjacent the corners of the girder, said strips being formed with reentrant flanges.

In witness whereof, I have hereunto signed my name.

BENJAMIN SCI-INITZER. 

